Roofing shingles comprising a fiberglass mat, organic or inorganic felt or fabric stock impregnated and coated with asphalt and covered with colored mineral granules are well known. For the most part, these have served as relatively inexpensive alternatives to tile, slate and wood roofing shingles. Although such asphaltic shingles are fire-resistant, give good protection and are durable, their substantially planar appearance has made them less pleasing to the eye and less imposing than their more expensive counterparts. Thus, asphalt shingles heretofore available are at a competitive disadvantage with the more expensive roofing shingles because they lack the irregular shadow appearing profiles and surface contours which are characteristic of roofs of wood or slate shingles.
Although lighter weight composite shingles having enhanced dimensionality are more desirable for ease of installation and handling, those which are currently marketed such as those described in U.S. Pat. Nos. 4,717,614; 3,921,358; 5,052,162 and Des. 247,786 are not amenable to stereospecific installation and must be mounted in one direction only on a roof surface. Although the former installability is much to the desired from the standpoint of minimizing material waste and adjustable alignment, no such dimensional shingle is available.
Many futile prior attempts have been made to provide asphalt shingles which would achieve the substantially structural and architectural appearance characteristic of wood or slate roofing shingles. For example, the prior art suggests that an asphalt shingle may be endowed with a massive ornamental effect by securing an additional strip beneath closely spaced tabs of a conventional shingle. However, the structure which is obtained, although massive, still provides only the regular, uniform butt edge profile and surface contour which denotes the common asphalt shingle and further adds to the overall shingle weight without any redeeming weathering advantage.
Also, manufacturers of asphalt shingles have sought to improve the appearance of asphalt shingles by producing them in many colors, and by varying the configuration of the tabs as in U.S. Pat. Nos. 2,194,427; 2,064,473; 2,199,760 and 2,171,010. Attempts have also been made to produce more irregular surface contours as in U.S. Pat. No. 2,099,131 which would give the shingle a bulkier appearance but these efforts have also failed. The goal of producing an inexpensive asphalt shingle providing the physical appearance of the more expensive shingle has until now eluded those skilled in the art.
Accordingly, it is an object of the present invention to overcome the above difficulties and objections and to produce a shingle having markedly increased planar irregularity with substantially no increase in weight by an economical and commercially feasible process.
Another object is to provide a shingle having the above advantages which is aesthetically pleasing and which more closely resembles wood shakes or slate roofing.
Still another object is to provide a unit shingle configuration which permits stereospecific installation of courses on a roof.
These and other objects of the invention will become apparent from the following description and disclosure.